1. Technical Field
The present disclosure relates to delay protection circuits, and particularly to a delay protection circuit with an adjustable delay time and an electronic device employing the delay protection circuit.
2. Description of Related Art
Many electronic devices employ delay protection circuits. A delay protection circuit may include a processor, a resistor, a capacitor, and a switch. When the delay protection circuit is used in an electronic device, the resistor is electrically connected to a power supply unit (PSU) of the electronic device, and the processor receives power output by the PSU via the resistor. If the power output by the PSU exceeds the rated power capacity of the electronic device, the processor controls the switch to electrically connect the capacitor with the PSU, and the PSU charges the capacitor via the switch. The processor detects a voltage on the capacitor during the charging process. Once the voltage on the capacitor achieves a predetermined and limited voltage, the processor turns off the PSU to protect the electronic device from being overpowered. The length of time for the voltage on the capacitor to achieve the predetermined voltage is identified as a delay time of the delay protection circuit. During the delay time, the electronic device can record current working processes and store data. Thus, the working processes and data are prevented from being lost when the PSU is turned off.
In the aforementioned electronic device, the delay time of the delay protection circuit cannot be adjusted. No matter how much the power output by the PSU exceeds the rated power capacity, the processor can only turn off the PSU after the fixed delay time has elapsed. If the power output by the PSU exceeds the rated power by a large margin, turning off the PSU after the delay time has elapsed may not protect the electronic device in time. Thus, the electronic device may be damaged by the excess power before the processor turns off the PSU (i.e., during the delay time). Further, if the power output by the PSU exceeds the rated power capacity only slightly, the PSU should not be turned off too quickly. This is because if the delay time is too short, the electronic device may not be able to timely store all the current working processes and data.
Therefore, there is room for improvement within the art.